Greenwood received his BA from Rice University in 1983, and went on to graduate from South Texas College of Law in 1986.He worked for the Harris County District Attorney's Office, starting as an intern in the Grand Jury Division and then the Trial Bureau after he became a licensed attorney.

Greenwood started his own law office in 1989, where he worked for 20 years focusing on representing police officers in criminal matters, such as officer-involved shootings and administrative proceedings.

He was also contracted with the Houston Police Officer's Association, Combined Law Enforcement Association of Texas, and the Houston Police Officer's Union.

In 2009, he joined the Harris County District Attorney's Office as the Police Integrity Division Chief. He moved to the Harris County Sheriff's Office in 2013, serving as the Commander of the Office of Inspector General, the Internal Affairs Division, and General Investigations Division.

"We knew him as a lawyer, law-enforcement officer and colleague respected in every role," District Attorney Kim Ogg said. "Our prayers are with his family."When Sheriff Ed Gonzales took office this year, Greenwood moved into his current role as Assistant Chief Deputy of Precinct 3.

"Thousands of men and women faithfully wear the badge of a Texas peace officer day in and day out in Houston and Harris County," stated Harris County Sheriff Ed Gonzalez. "They answer a high call to service for their fellow man. That was the call that Assistant Chief Clint Greenwood answered over decades of service. His bravery and sacrifice will not be forgotten and will not go unanswered."

Lt. Gov. Dan Patrick issued this statement: "Violence against our law enforcement officers must stop. Protecting our men and women in uniform continues to be a top priority for me and I will do whatever it takes to bring this latest assassin to justice."

New recruits had the benefits of learning from Greenwood as he served as an instructor for the Houston Police Department from 2009 to 2012.